U.S. Philips Corporation

Thomson Trt Defense

Joel Rollin

Jean-Claude Perrin

Fernand R Loy

Jean-Claude Bourgeois

Thierry Benchetrit

The present invention concerns device for the acquisition of the angular position of mobile means of the type including a luminous source emitting an incident beam in a known direction and a reflecting surface attached to the mobile means. The device also includes an array of elementary charge coupled sensors positioned so as to be at least partly scanned by the reflected beam. The device includes in addition optical means for limiting the width of the incident beam. The said array is connected to an electronic circuit producing a digital signal varying according to the position and/or the number of elementary sensors illuminated by the reflected beam.

Device for the acquisition of the instantaneous angular position of

An infrared objective device with optical achromatization and athermalization comprises a front convergent assembly having at least one divergent lens acting as a port and one convergent lens, and a rear divergent assembly comprising at least one divergent lens. These three lenses are chosen so as to be made of three different materials of the type that can be used in the 8 to 12 .mu.m spectral band. They may notably be made, respectively, of germanium, chalcogenide and zinc sulphide.

Systems of objectives with optical athermalization

The bifocal optical system is formed in the long focal length mode by an objective having fixed lenses L1, L2, L3, L4 to which, for obtaining the short focal length, a group of movable lenses L5, L6, L7, L8 is added. The lenses L5, L6, L7 and L8 are accommodated in a holder (MB) which is rotatable around an axis YY' which extends parallel to the optical axis XX', thereby enabling very wide tolerances in the positioning of the movable holder.

Bifocal optical system

This varifocal optical system is electro-mechanically controlled to vary focal distance, temperature correction focussing and finite distance focussing. It is constituted by four single lenses (L1, L2, L3 and L4) two of which (L2, L3) are movable and are axially translated to vary the magnification, while only one (L3) of these two lenses is adapted for temperature correction focussing and finite distance focussing. It is also consituted by electro-mechanical member (EMM) which are especially adapted to control the movements of the two movable lenses (L2, L3) in a discrete manner.

Varifocal optical system and associated electro-mechanical control

Device used in aviation for in-flight reception of images corrects distortion resulting from the observation of a field of view through a wall (1) which is transparent in a given spectral band and whose shape distorts the image of the scene formed on a receiver (4). An optical system arranged between the receiver and the wall performs an anamorphotic function in one direction and a deviation function in another direction perpendicular thereto. The deviation function is realized by a single prism formed by two parts (5,6) cemented to one another and which have different refractive indices so as to form an achromatic assembly. The anamorphotic function is obtained by a slight change of the focal length of the receiver in conjunction with the elongation of lines formed by the prism in the direction of the deviation function.

Device for correcting the total distortion caused by the shape of a

Device for correcting the differential distortion resulting from simultaneous observation of a field of view at two distinct locations through a shield transparent in a given spectral band, which shield has a shape generating the distortion when a receiver which is sensitive in the spectral band is arranged at each of the locations. The correction is effected by an optical system arranged between the shield and one or the other receiver and comprising an anamorphic assembly (11, 12) producing an anamorphosis in a first direction associated with an element (13) introducing a curvature in a second direction, while the distortion produced by this system has a direction opposite to the differential distortion.

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Vanves, France

Joel Rollin